[LeetCode]Maximum Product Subarray

Find the contiguous subarray within an array (containing at least one number) which has the largest product.

For example, given the array [2,3,-2,4],
the contiguous subarray [2,3] has the largest product = 6.

发现leetcode又更新了一道题

Analysis:

similar like Maximum Subarray question

difference is the max value could be get from 3 situations

current maxValue * A[i]  if A[i]>0

current minValue * A[i]  if A[i]<0

A[i]  

We need to record current maxValue, current minValue and update them every time get the new product

Java

public int maxProduct2(int[] A) {if(A.length<=0) return 0;if(A.length==1) return A[0];int curMax = A[0];int curMin = A[0];int ans = A[0];for(int i=1;i<A.length;i++){int temp = curMin *A[i];curMin = Math.min(A[i], Math.min(temp, curMax*A[i]));curMax = Math.max(A[i], Math.max(temp, curMax*A[i]));ans = Math.max(ans, curMax);}return ans;}